In what way has Taylor's life been "running along on dumb luck," and what is the significance of the fact that she "[Has]n't even noticed"?

DEspite her own hardships, Taylor realized that her life has been "dumb luck" compared to Estevan's and Esperanza's. Taylor realizes that all her bad luck became a sort of serendipity.She blew out a tire, but found Mattie and an Indian mother gave her a baby that she would fall in love with. Taylor only realizes her "dumb luck" when she realizes how life has turned out for Estevan and Esperanza.